1. Field of Invention
The present invention relates to a survey apparatus in which an angle and distance measuring apparatus and a GPS survey machine are combined, and a survey method for using this survey apparatus.
2. Description of Related Art
Angle and distance measuring apparatus, a so-called "total station", is often used for a survey in civil engineering and construction work, and other surveys. This total station is a high performance angle and distance measuring apparatus in which a main microcomputer and multiple auxiliary microcomputers are installed in combination. This angle and distance measuring apparatus maintains a horizontal-rotation axis vertical, and a vertical-rotation axis horizontal, using a leveling table. Thus, this angle and distance measuring apparatus is able to measure with a high degree of accuracy horizontal direction angles about the horizontal-rotation axis and vertical direction angles about the vertical-rotation axis of a collimation telescope. In addition, this angle and distance measuring apparatus is able to measure with a high degree of accuracy the distance to a collimated target by performing a light wave measurement using a high luminance LED or the like.
This total station is installed on the vertical line above a survey point using a tripod. Then other survey points are collimated and measured from this survey point using the collimation telescope. This total station measures the horizontal direction angle from the reference direction to the collimation object survey point, and the vertical direction angle of the collimation object survey point with respect to the horizontal direction using a rotary encoder or the like. A pulse signal emitted from the rotary encoder is supplied to an angle measuring sub-CPU, which serves as an angle measuring microcomputer. The angle measuring CPU processes the pulse signal, and stores the angle data in the horizontal direction and the angle data in the vertical direction in its memory. In addition, this total station generates light waves using the high luminance LED, and projects the light waves onto the collimation point that has been collimated using the collimation telescope. When the light waves are reflected at the collimation point, a distance measuring sub-CPU, which serves as a distance measuring microcomputer, analyzes the reflected light, and stores in its memory the data on the distance to the collimation point.
When this total station, which is used for a collimation survey, receives commands from the keyboard, the main CPU, which serves as the main microcomputer, controls a display unit 31 so as to display on its display screen the angle data and distance data stored in the angle measuring microcomputer and the distance measuring microcomputer, respectively. The total station then transfers the respective data to an externally connected personal computer as needed.
In recent years, various kinds of surveys have been performed with the use of a global positioning system (GPS). In conducting a GPS survey, a receiving antenna and a receiver are used to receive radio waves from multiple GPS satellites. The received data is then stored in a memory built in the receiver or a flexible disk or a cassette tape, or the like. The received data is analyzed and the values of the coordinates of the position of the receiving antenna are calculated.
In storing in a memory or the like the data the GPS antenna has received, a file for storing the observation data to be received is created and is given a name before the reception of the observation data is started. This file is stored in a memory or the like. In a single positioning GPS survey, a single receiving antenna is used to measure the coordinates of the position of the receiving antenna. In a relative positioning GPS survey, several receiving antennas are used to measure the coordinates of the position of each of the receiving antennas. In a single GPS survey, a real time coordinate measurement is possible. However, in this case, the measurement error sometimes exceeds several tens of meters. For this reason, a single GPS survey is not currently in use. There are relative survey methods of various degrees of accuracy. For example, in a relative positioning GPS survey, called DGPS, each of the several receiving antennas performs a single positioning GPS survey. The coordinates of the position of each of the receiving antennas are measured based on the observation data received by the other receiving antennas. In this DGPS, when the coordinates of each receiving antenna are analyzed, if the exact position of at least one of the receiving antennas is known, the difference between the coordinates of the position of the receiving antenna, which the DGPS has obtained by analyzing the received data, and the coordinates of the receiving antenna installed at a known coordinate is calculated. In DGPS, this difference is used as a correction value for correcting the coordinate value of each of the receiving antennas that has been obtained by single positioning. By performing this correction, the DGPS can measure by real time the position of each of the other receiving antennas that the DGPS has simultaneously obtained by single positioning. In this case, the range of error of the measurement lies within several meters. In the real time kinematic GPS positioning method, which is a kind of relative GPS positioning method, data received by several receiving antennas is analyzed together. According to the real time kinematic GPS positioning method, the coordinate position of each of the receivers can be measured within an error margin of several centimeters. In the static GPS positioning method, several receiving antennas need to receive radio waves continuously from a satellite for a prescribed length of time. However, the static GPS positioning method is able to reduce the measurement error to less than one centimeter.
Therefore, the real time kinematic GPS and static GPS are currently in use for surveys. In using the relative GPS, when the coordinates of the position of each of the receiving antennas, which is a GPS antenna, are measured, the absolute error exists between the true coordinate values, which are true values of the coordinates of each the receiving antennas, and the measured coordinate values of the receiving antenna. Therefore, the values of the measurement result contain an error of large magnitude when the distances between the GPS antennas are small. On the other hand, when the distances between the GPS antennas are large, the measurement error can be made very small. In this case, the GPS survey can be performed with a high degree of accuracy.
For this reason, today, in surveying between visually recognizable survey points that are located within a relatively short distance, a collimation survey is performed, in which an angle and distance measuring apparatus such as the above-mentioned total station is used. A GPS survey is often used when the survey points are separated by distances that are too long to be visually recognized. For example, in the case in which a new reference point is installed, when no reference point whose exact coordinates are known exists nearby, a GPS survey is used so as to install this new reference point at the exact coordinate position.
In performing a survey that uses a GPS or the above-described angle anddistance measuring apparatus, the position of a new survey point is first determined approximately on the topographical map. A work plan that suits the survey object is then made. In making this work plan, a reconnaissance diagram is constructed on the topographical map. The reconnaissance diagram is constituted of required survey points that are determined approximately on the topographical map so as to suit the objective. The required number of the survey points and the positions of the survey points are determined with reference to an average plan diagram so as to complete the reconnaissance map. The average plan diagram that is used in this case shows a polygonal net. Using this polygonal net, the error contained in the distance between the survey points can be corrected by the net average, enabling easy calculation of the exact survey point coordinates.
Next, based on the completed reconnaissance diagram, a reconnaissance work is carried out. In this reconnaissance work, known survey points that are usable on the survey sites and the positions of new survey points are selected. A permanent sign or temporary sign is then installed at each of the new survey points. By investigating the sites, the positions of the survey points on the average plan diagram are modified so that they will suit the conditions on the sites. This modified average plan diagram is then used as an average diagram.
In addition, in a collimation survey, in which an angle anddistance measuring apparatus is used, an observation diagram is constructed. The observation diagram is constructed based on the reconnaissance diagram and average diagram so as to determine survey points at which the angle and distance measuring apparatus is to be installed and so as to determine which of the survey points are to be observed by collimation from the installed angle anddistance measuring apparatus. Based on this observation diagram, an observation execution plan is determined including the work process such as the order of observation. After this, survey work is carried out based on this observation execution plan. In the survey work, in accordance with the order of observation, the angle anddistance measuring apparatus is first installed at the first survey point, where a survey sign is installed. At the other survey points, at each of which a survey sign is installed, for example, a corner cube prism or the like is installed on the vertical line above the respective survey point. The corner cube prism is used to measure the horizontal direction angle, vertical direction angle, and straight line distance from the angle anddistance measuring apparatus to the corner cube prism. When these quantities have been measured, the obtained observation data is recorded.
In obtaining and recording this observation data, the machine type of the survey apparatus and the names of the observers are also recorded as part of the data. The observation data includes: (1) the name of the work, (2) the machine type of the survey apparatus and the machine number, (3) the names of the observers and the year, month, and day of the observation, (4) the weather, wind force, temperature, and atmospheric pressure on the observation day, (5) the names of the survey point at which the survey apparatus has been installed and remarks including the sign numbers, the height of the installed survey apparatus, the offset direction and offset distance from the survey sign to the survey apparatus, the pair count, that is the required number of times to conduct the measurement, the set number, the direction number, the start time and the end time, (6) the names of the collimation points, the heights of the objects, the observation number, the observed value of the horizontal angle, the observed value of the vertical angle, and the measured value of the oblique distance. The observation data is listed and recorded in the above-described order.
In obtaining and recording this observation data, the machine type and machine number of the survey apparatus are recorded in the main microcomputer that is built in the total station and are copied as observation data on the memory by a key operation on the keyboard. When a collimation point is collimated using the collimation telescope by the "save" operation on the keyboard, the observed values of the angle and distance are recorded as observation data in the angle measuring microcomputer and distance measuring microcomputer, respectively.
However, the other observation data is individually input and recorded by typing numbers and letters on the keyboard. When the observation of one collimation point is finished, the name of the next collimation point as input data is typed on the keyboard. The height of the object and the observation number of the collimation point having this collimation point name are then input from the keyboard. The next collimation point is collimated using the collimation telescope. The observed values of the horizontal angle, vertical angle, and oblique distance are saved by the required number of times. The collimation point name, height of the object, observation number, observed values of the horizontal angle, vertical angle and oblique distance are sequentially stored and recorded in the memory, in this order.
When the installation position of the total station has been changed, the survey point name, remarks, installation height, offset distance and the like are input from the keyboard, and are saved in the memory. Then the observation is continued. After the survey work on the site is finished, the above-described observation data is usually taken back to the office where the observation data is automatically processed and analyzed using a computer in which after-process software is installed. Based on the analyzed observation data, the survey result is recorded as a document.
Today, as has been described above, in conducting an observation survey between visually recognizable survey points that are located within a relatively short distance, an angle and distance measuring apparatus such as the total station is usually used. A GPS survey is often used when the survey points are separated by a long distance. However, when there is no known point, the exact coordinates of which are known, among the group of survey points, or when a known point to be used as a reference point, the exact coordinates of which are known, does not exist near the group of survey points, a GPS survey using a GPS survey machine is combined with a collimation survey using an angle anddistance measuring apparatus.
For this reason, a plan to use a survey apparatus in which an angle anddistance measuring apparatus and a GPS survey machine are combined by attaching a GPS antenna to the angle anddistance measuring apparatus, such as a total station, is proposed. However, as has been explained before, in order to conduct a GPS survey with a high degree of accuracy, the data received by the GPS antenna at the site needs to be combined with the data received by the other GPS antennas located at remote locations. Therefore, the data received by the GPS antenna attached to the angle anddistance measuring apparatus is combined with the data received by the other GPS survey machines so as to calculate the installation coordinates of the survey apparatus at the site. The observation data obtained by a collimation survey using the angle anddistance measuring apparatus is analyzed and is used to calculate the position of the survey point. Based on this analyzed observation data, the topography of the site is obtained. The installation coordinates of the survey apparatus, which has been obtained by analyzing the data received by the GPS antennas, is combined with the observation data that has been obtained by using the angle anddistance measuring apparatus. The result of the survey is summarized in this way.
As has been explained before, in conducting a survey between visually recognizable survey points, a collimation survey is often conducted with the use of an angle and distance measuring apparatus such as a total station. In conducting a collimation survey, the survey point names, which constitute important data, are manually input from the keyboard. Therefore, a human error can occur while typing the survey point names. When this input data containing an input error is analyzed, the data analysis is often disabled due to the error in the data. If the correct survey point names are found by comparing the input data with the work plan, the observation data is corrected, and the corrected observation data is analyzed and calculated again. In this way, the correct observation result is obtained.
However, when the survey point names are sequentially confirmed based on the observation execution plan, and the data analysis calculation is repeated after the survey point names that contradict the survey point names listed on the observation execution plan have been corrected, the reliability of the survey result deteriorates. In addition, when a wrongly input survey name happens to coincide with the name of another survey point, this error cannot be detected immediately. In this case, the data analysis calculation produces a wrong result.
Thus, in a collimation survey that uses an angle and distance measuring apparatus, it is not always possible to obtain a correct survey result no matter how carefully and precisely the collimation work is conducted, since a human error can occur in inputting survey point names. Moreover, when the angle and distance measuring apparatus is installed at a wrong installation point, the observed data cannot be used to analyze the survey result or the survey result does not fit in the admissible range of error. In such a case, the survey needs to be repeated.
In re-conducting a survey, when the survey site is in a remote location, or when the transportation to the survey site is inconvenient, an enormous amount of time is needed in order to commute to the site, in addition to the time and effort required to re-conduct the survey work.
U.S. Pat. No. 5,077,557--Ingensand entitled SURVEYING INSTRUMENT WITH RECEIVER FOR SATELLITE POSITION-MEASURING SYSTEM AND METHOD OF OPERATION and U.S. Pat. No. 5,233,357--Ingensand et al entitled SURVEYING SYSTEM INCLUDING AN ELECTRO-OPTIC TOTAL STATION AND A PORTABLE RECEIVING APPARATUS COMPRISING A SETELLITE POSITION-MEASURING SYSTEM are hereby incorporated herein by reference as if fully set forth.